Victims' families reacted angrily last night to the release from prison of loyalist supergrass Gary Haggarty.
The BBC reported that the former UVF leader who turned assisting offender was freed to a secret location on a witness protection scheme.
He had been sentenced to six-and-a-half years just over three months ago for over 500 offences including five murders, but Haggarty had spent more than four years in jail.
The Public Prosecution Service (PPS) is appealing the sentence.
Padraig O'Muirigh, a solicitor representing families of Haggarty's victims, said they were distraught although it was not a complete surprise to them.
"In their view Gary Haggarty is effectively a serial killer and in their minds treated more favourably than them," he told the BBC.
"It is very difficult for the families. They have been through this very long process with the assisting offender trial we had and at the end of that we now have Mr Haggarty being released."
Mr O'Muirigh said that while they were aware of the dates of Haggarty's likely release, "they did expect to be notified" before it took place. SDLP MLA Dolores Kelly said Haggarty's release should have been held until the PPS's appeal was heard.
Haggarty had been sentenced to 35 years in jail, but given his guilty pleas and his agreement to become an assisting offender, his final sentence was reduced significantly.
The former boss of the notorious Mount Vernon unit of the UVF in north Belfast was a long-time police informer and pleaded guilty to a litany of serious crimes.
The catalogue of offences stretch over 16 years from 1991 to 2007 and include the loyalist murders of John Harbinson, Sean McParland, Gary Convie, Eamon Fox and Sean McDermott.
As well as the five murders, Haggarty admitted five attempted murders, including against police officers; 23 counts of conspiracy to murder; directing terrorism; and membership of a proscribed organisation.
The vast majority of individuals named by Haggarty in his police interviews will not face prosecution amid State concerns about a lack of supporting evidence. The Department of Justice said it would not comment on his release.